In the art of laboratory chemical testing, various devices for carrying out diagnostic and other tests exist. Of particular interest today are inexpensive and preferably disposable devices which are convenient to use, yet do not dispense with the accuracy of the test performed thereby.
Currently, most disposable and/or less expensive type devices consist of two or more injection molded components which are assembled together or with other additional components. Typically, the tolerances required on the components and during assembly are very tight which contributes to high manufacturing costs. Also, many devices require during operation the application of external forces, such as mechanical agitation or a magnetic field for mixing reactants, to induce the desired chemical reaction. Such a requisite adds to operating costs of the devices.
For example, C. Coleman in U.S. Pat. No. 3,799,742 discloses a miniaturized unitary analytical test container. That device receives a specimen of interest in a reception chamber through a narrow first passageway. The specimen is transferred from the reception chamber to a filter or separation chamber through a second narrow passageway. From the filter, the specimen flows into two reaction chambers through respective conduits to the reaction chambers. A predefined amount of desired reagents are prepackaged in the reaction chambers, i.e. during manufacturing. Lead bead elements are also placed in the reaction chambers during manufacturing and act to facilitate mixing of the filtered specimen and reagent material in the chambers with application of external forces for mixing (e.g. mechanical agitation or a magnetic field). Such mixing makes the desired chemical reaction possible.
In another example, U.S. Pat. No. 4,775,515 to Cottingham discloses a device for carrying out an immunochemical particle agglutination reaction without the necessity of shaking, rocking or otherwise adding external kinetic energy thereto. The device is a slide with a channel into which liquid sample and reagents are introduced at one end. The reaction mixture is attracted to the surfaces of the channel walls and is drawn forward under capillary forces to the opposite end of the channel. During capillary flow, agglutination occurs. Coextensive with the opposite end of the channel is a viewing chamber, in which the reaction products can be observed visually or by suitable instruments. Although operating costs of this device are reasonable, manufacturing costs of the device are substantial due to the slide and channel configurations required for capillary action.
In U.S. Pat. No. 3,888,629 to Bagshawe, a testing reaction device with a predetermined amount of reactant and/or reagent contained in a porous matrix pad is disclosed. The matrix pad is supported in a container in a manner that allows sample fluid to pass from one side to another side of the pad in the container under forces of gravity. The sample fluid reacts with reactants and/or reagents contained in the matrix pad while flowing therethrough and forms a liquid product which is gathered in an end of the container and a particulate product which is retained in the matrix pad. However, such a device is costly to manufacture because different matrix pads with various reagents and/or reactants are needed for desired various reactions. Further, this type of device is not appropriate for many reaction types. The device is designed mainly for use with radioimmunoassay systems.
Accordingly, there is a need for an inexpensive and preferably disposable device useful for carrying out assays, including diagnostic tests.